Embodiments of the present disclosure include a harmonic power amplifying circuit with high efficiency and high bandwidth and a radio-frequency power amplifier. The circuit comprises an input matching network (11), a transistor (M), and an output matching network (12); a gate of the transistor (M) connected to an output end of the input matching network (11), a drain thereof connected to an input end of the output matching network (12), and a source thereof being grounded; wherein the output matching network (12) enables a lower sideband of the harmonic power amplifying circuit to work in a continuous inverse F amplification mode and an upper sideband of the harmonic power amplifying circuit to work in a continuous F amplification mode; wherein the output matching network (12) and a parasitic network of the transistor (M) form a low pass filter. By transitioning from the continuous inverse F power amplifier working mode to the continuous F power amplifier working mode, the efficiency of a continuous harmonic control power amplifier is effectively improved to be higher than 60%, a relative bandwidth is improved to be higher than 80%, and the harmonic impedance is simple to match and easy to realize.

A power amplifier circuit includes a power splitter, a first amplifier, a second amplifier, a third amplifier, a fourth amplifier, a first bias circuit, a first line connecting the first bias circuit and the first amplifier, and a second line connecting the first bias circuit and the third amplifier on the same semiconductor substrate, in which the first line and the second line are formed such that a voltage drop amount of the first bias voltage between the first bias circuit and the first amplifier is substantially equal to a voltage drop amount of the first bias voltage between the first bias circuit and the third amplifier.

An RF amplifier includes an amplifier input, a transistor die with a transistor and a transistor input terminal, a fundamental frequency impedance matching circuit coupled between the amplifier input and the transistor input terminal, and a harmonic frequency termination circuit coupled between the transistor input terminal and a ground reference node. The harmonic frequency termination circuit includes a first inductance coupled between the transistor input terminal and a first node, and a tank circuit coupled between the first node and the ground reference node. The tank circuit includes a first capacitance coupled between the first node and the ground reference node, and a second inductance coupled between the first node and the ground reference node. The tank circuit is configured to shunt signal energy at or near a second harmonic frequency, while appearing as an open circuit to signal energy at a fundamental frequency of operation of the RF amplifier.

A power amplifier circuit includes an input-stage power amplifier configured to receive a radio-frequency input signal, an output-stage power amplifier configured to output an amplified radio-frequency output signal, and an intermediate-stage power amplifier disposed between the input-stage power amplifier and the output-stage power amplifier. The intermediate-stage power amplifier includes a first transistor, a second transistor, and a capacitor having a first end connected to an emitter of the first transistor and a second end connected to a collector of the second transistor. The intermediate-stage power amplifier receives a signal at a base of the second transistor thereof and outputs an amplified signal from a collector of the first transistor thereof.

An amplifier includes an input matching network; at least one transistor; an input lead coupled to the at least one transistor; a ground terminal coupled to the transistor; an output lead coupled to the at least one transistor; an output matching circuit coupled to the output lead and to the at least one transistor; and a baseband impedance enhancement circuit having at least one reactive element coupled to the input matching network. The baseband impedance enhancement circuit is configured to reduce resonances of a baseband termination.

An amplifier includes a semiconductor die and a substrate that is distinct from the semiconductor die. The semiconductor die includes a III-V semiconductor substrate, a first RF signal input terminal, a first RF signal output terminal, and a transistor (e.g., a GaN FET). The transistor has a control terminal electrically coupled to the first RF signal input terminal, and a current-carrying terminal electrically coupled to the first RF signal output terminal. The substrate includes a second RF signal input terminal, a second RF signal output terminal, circuitry coupled between the second RF signal input terminal and the second RF signal output terminal, and an electrostatic discharge (ESD) protection circuit. The amplifier also includes a connection electrically coupled between the ESD protection circuit and the control terminal of the transistor. The substrate may be another semiconductor die (e.g., with a driver transistor and/or impedance matching circuitry) or an integrated passive device.

The present invention is directed to communication systems and electrical circuits. According to an embodiment, the present invention provides a termination circuit that includes an inductor network. The inductor network is coupled to a termination resistor and a capacitor network, which includes a first capacitor and a second capacitor. The termination resistor, the first capacitor, and the second capacitor are adjustable, and they affect attenuation of the termination circuit. There are other embodiments as well.

A semiconductor device includes: a conductive base substrate; a semiconductor chip mounted on the base substrate and having a signal pad; a frame configured to surround the semiconductor chip, to be mounted on the base substrate, and to include a step having an inner first upper surface and an outer second upper surface higher than the first upper surface in a plan view, wherein a first conductor pattern provided on the first upper surface is electrically connected to the base substrate; a capacitive component mounted on the first conductor pattern; a signal terminal mounted on the second upper surface of the frame; a first bonding wire configured to electrically connect the signal pad and an upper surface of the capacitive component; and a second bonding wire configured to electrically connect the upper surface of the capacitive component and the signal terminal.

In some embodiments, stability in power amplifiers can be achieved under high in-band voltage standing wave ratio condition, with an amplifier circuit that includes an amplifier having a first stage and a second stage, with each stage including an input and an output, such that the output of the first stage is coupled to the input of the second stage. The amplifier circuit further includes a stabilizing circuit implemented on the input side of the second stage and configured to provide stability in operation of the amplifier under a high in-band voltage standing wave ratio condition.

A matching circuit includes first and second ports, an autotransformer, and first and second capacitors. The autotransformer includes a first terminal coupled to a first port, a second terminal coupled to a second port, and a common terminal coupled to a reference potential, and includes a series parasitic inductor and a parallel parasitic inductor. The first capacitor is coupled in shunt to the second terminal, and defines a low pass filter together with the series parasitic inductor. The second capacitor is coupled in series between the first port and the first terminal, and defines a high pass filter together with the parallel parasitic inductor.